[LU-6711] INFO: possible recursive locking detected, ofd_lastid_rwsem

Sun, 10 Oct 2021 21:25:05 +0000
I got this while mounting an OST on a debug kernel. I have no idea if the bug is valid or not, but I thought I'd report the error in case it was useful.
[  503.252254] =============================================
[  503.252261] [ INFO: possible recursive locking detected ]
[  503.252268] 3.10.0-229.4.2.el7.centos.x86_64.debug #1 Tainted: GF          O--------------  
[  503.252279] ---------------------------------------------
[  503.252286] ll_ost00_003/2126 is trying to acquire lock:
[  503.252294]  (&m->ofd_lastid_rwsem){.+.+.+}, at: [<ffffffffa0d6b31f>] ofd_statfs_internal+0x4f/0x3a0 [ofd]
[  503.252325] 
but task is already holding lock:
[  503.252331]  (&m->ofd_lastid_rwsem){.+.+.+}, at: [<ffffffffa0d5f471>] ofd_create_hdl+0x1f1/0x2a10 [ofd]
[  503.252351] 
other info that might help us debug this:
[  503.252359]  Possible unsafe locking scenario:

[  503.252367]        CPU0
[  503.252370]        ----
[  503.252386]   lock(&m->ofd_lastid_rwsem);
[  503.252395]   lock(&m->ofd_lastid_rwsem);
[  503.252411] 
 *** DEADLOCK ***

[  503.252422]  May be due to missing lock nesting notation

[  503.252433] 2 locks held by ll_ost00_003/2126:
[  503.252441]  #0:  (&m->ofd_lastid_rwsem){.+.+.+}, at: [<ffffffffa0d5f471>] ofd_create_hdl+0x1f1/0x2a10 [ofd]
[  503.252475]  #1:  (&oseq->os_create_lock){+.+...}, at: [<ffffffffa0d5f50f>] ofd_create_hdl+0x28f/0x2a10 [ofd]
[  503.252506] 
stack backtrace:
[  503.252517] CPU: 0 PID: 2126 Comm: ll_ost00_003 Tainted: GF          O--------------   3.10.0-229.4.2.el7.centos.x86_64.debug #1
[  503.252533] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153950- 04/01/2014
[  503.252545]  ffffffff827ff170 0000000024fc9851 ffff88000f10b948 ffffffff816c7301
[  503.252559]  ffff88000f10b998 ffffffff810fdd11 00000000810cac28 000000125c9c0401
[  503.252572]  ffffffff8240a940 0000000000000002 ffff88000f098000 000000125c9c0497
[  503.252584] Call Trace:
[  503.252593]  [<ffffffff816c7301>] dump_stack+0x19/0x1b
[  503.252601]  [<ffffffff810fdd11>] validate_chain.isra.43+0x891/0x910
[  503.252610]  [<ffffffff810fec26>] __lock_acquire+0x3c6/0xb60
[  503.252618]  [<ffffffff8105e144>] ? kvm_clock_read+0x34/0x40
[  503.252626]  [<ffffffff810ffb99>] lock_acquire+0x99/0x1e0
[  503.252637]  [<ffffffffa0d6b31f>] ? ofd_statfs_internal+0x4f/0x3a0 [ofd]
[  503.252646]  [<ffffffff816cd691>] down_read+0x51/0xa0
[  503.252657]  [<ffffffffa0d6b31f>] ? ofd_statfs_internal+0x4f/0x3a0 [ofd]
[  503.252669]  [<ffffffffa0d6b31f>] ofd_statfs_internal+0x4f/0x3a0 [ofd]
[  503.252739]  [<ffffffffa0d7c123>] ofd_grant_statfs+0x73/0x180 [ofd]
[  503.252802]  [<ffffffffa0d7edbc>] ofd_grant_create+0xbc/0x420 [ofd]
[  503.252865]  [<ffffffffa0d5f5c4>] ofd_create_hdl+0x344/0x2a10 [ofd]
[  503.252983]  [<ffffffffa0793eac>] ? lustre_pack_reply_v2+0x16c/0x2a0 [ptlrpc]
[  503.253010]  [<ffffffffa07efcb8>] tgt_request_handle+0x6e8/0x1080 [ptlrpc]
[  503.253010]  [<ffffffffa079f171>] ptlrpc_server_handle_request+0x231/0xad0 [ptlrpc]
[  503.253010]  [<ffffffffa03f7bc8>] ? lc_watchdog_touch+0x68/0x180 [libcfs]
[  503.253010]  [<ffffffffa079d9b8>] ? ptlrpc_wait_event+0xb8/0x370 [ptlrpc]
[  503.253010]  [<ffffffff810fa29f>] ? lock_release_holdtime.part.28+0xf/0x1a0
[  503.253010]  [<ffffffffa07a3518>] ptlrpc_main+0xb28/0x1f40 [ptlrpc]
[  503.253010]  [<ffffffff816d074c>] ? _raw_spin_unlock_irq+0x2c/0x50
[  503.253010]  [<ffffffffa07a29f0>] ? ptlrpc_register_service+0xf30/0xf30 [ptlrpc]
[  503.253010]  [<ffffffff810b05ed>] kthread+0xed/0x100
[  503.253010]  [<ffffffff810b0500>] ? insert_kthread_work+0x80/0x80
[  503.253010]  [<ffffffff816dac3c>] ret_from_fork+0x7c/0xb0
[  503.253010]  [<ffffffff810b0500>] ? insert_kthread_work+0x80/0x80
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[LU-6711] INFO: possible recursive locking detected, ofd_lastid_rwsem
